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98 5.7 Vortec Performance Upgrade Questions

This is a discussion on 98 5.7 Vortec Performance Upgrade Questions within the Port Injection (96+ / OBD-II) forums, part of the Performance category; I have a bone stock 98 C1500 5.7L 350 Vortec. I have modded the exhaust a little bit, though still ...

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    98 5.7 Vortec Performance Upgrade Questions


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    I have a bone stock 98 C1500 5.7L 350 Vortec. I have modded the exhaust a little bit, though still running the stock manifolds and exhaust piping. I will also be adding a cold air intake in the next few days. What are some performance mods that will give me a good amount of torque and hp for not alot of money? Headers are probably out of the question, though shorties might be a possibility. I'm looking for a cam, maybe roller rockers, and stuff like that. I'm new to all the technical stuff like that so I have no idea what I need or what all will be involved with it. The truck is my daily driver, and sees mostly street use, and I don't really do any towing, just want more power. Any advice would be greatly appreciated! Also, please include the links to the parts ya'll list, so I know where to find them and how much they'll be.
    '98 chevy silverado ecsb- true dual exhaust, two Flowmaster Super 44 mufflers, 4" ss tips, coil spring spacers, 31X10.5X15 BFG T/A KO tires, 5% tint all around, Kenwood Excelon speakers/headunit, 6000K HID's

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    Registered User 96ImpSS's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    In order of best bang for the buck
    1. Custom tune. PCMforLess has a great mail order tune for your truck, developed on the dyno with mine when it had the stock cam.
    2. A tight stall 9.5" or 10" converter
    3. Gears. What do you have now? If 3.42 or less, go with at least 4.10's with your tire size. If you already have 3.73's, might want to leave them.
    4. Headers, preferably longtubes. Shorties still better than nothing, and you can keep your stock cats/headpipes.

    Cold air intake will net you nothing over the factory intake.
    A cam would be a waste without headers.
    Roller rockers are not a very good bang for buck mod on this engine.

    Mine dyno'd 254 rwhp and ran 14.9's in good weather with only the pcmforless tune, longtube headers, Vig 3000 converter, and single 3" exhaust.
    Edit: also had a Transgo kit in it.
    Last edited by 96ImpSS; 01-06-2011 at 07:12 AM.
    '98 XCSB, ZZ4 cam, Tri-Y's, Yank SS3600 TC
    PCMFORLESS.COM 87 octane tune
    14.30 @ 92.2 on motor
    13.47 @ 99.2 w/ a 50 dry shot

    '96 ImpalaSS
    10.98 @ 122 NA, 10.35 @ 128 on a 100 shot
    stock bottom LT1

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    Registered User culookn's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    i added a cam, longtubes & catback and could defiently tell the difference in the low end
    97 K2500 7.4 Whipple

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    Did someone say ponies? The Fiddle's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Quote Originally Posted by 96ImpSS View Post
    In order of best bang for the buck
    1. Custom tune. PCMforLess has a great mail order tune for your truck, developed on the dyno with mine when it had the stock cam.
    2. A tight stall 9.5" or 10" converter
    3. Gears. What do you have now? If 3.42 or less, go with at least 4.10's with your tire size. If you already have 3.73's, might want to leave them.
    4. Headers, preferably longtubes. Shorties still better than nothing, and you can keep your stock cats/headpipes.

    Cold air intake will net you nothing over the factory intake.
    A cam would be a waste without headers.
    Roller rockers are not a very good bang for buck mod on this engine.

    Mine dyno'd 254 rwhp and ran 14.9's in good weather with only the pcmforless tune, longtube headers, Vig 3000 converter, and single 3" exhaust.
    Edit: also had a Transgo kit in it.
    kee kee kee









    ...but true.
    2005 Pontiac GTO LS2/A4. FPFQ'ing the GTO community.
    1999 OBS K1500 Black Bear tuned 383 Z71. 2" rear blocks, Hankook MT's. Still around.

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    Its always somethin Ghostyman25's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Quote Originally Posted by The Fiddle View Post
    kee kee kee









    ...but true.
    Im gonna gues you learned this the hard way?
    White 1993,c1500,rcss,--TOTALED 8/20/10
    White 1999 1500 / Rcsb-TOTALED 5/19/11

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    Did someone say ponies? The Fiddle's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Quote Originally Posted by Ghostyman25 View Post
    Im gonna gues you learned this the hard way?
    Still am.


    383 + stock exhaust manifolds = WTF.
    2005 Pontiac GTO LS2/A4. FPFQ'ing the GTO community.
    1999 OBS K1500 Black Bear tuned 383 Z71. 2" rear blocks, Hankook MT's. Still around.

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    Its always somethin Ghostyman25's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Quote Originally Posted by The Fiddle View Post
    Still am.


    383 + stock exhaust manifolds = WTF.
    At least say it doesnt have stock exhaust under it!
    White 1993,c1500,rcss,--TOTALED 8/20/10
    White 1999 1500 / Rcsb-TOTALED 5/19/11

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    I Hate You All, Equally.
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    A set of long tube headers would end up being cheaper than shorties and way worth it, just requires some exhaust modification, but i would get an off road y-pipe (ORY) and then you replace all the bottlenecks in the system in one shot.


    1983 Jimmy Sierra Classic-Future LSX Swap Recipient
    2002 Silverado 2500HD CCSB LT-Daily Driver
    1995 Corsica-Super-Sleeper in Progress

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    Re: 98 5.7 Vortec Performance Upgrade Questions

    I think you'll be surprised by what a tune will do for you. Off the top of my head, I removed all of the brake tq management, removed the 4 second PE enable delay, turned off abuse mode, added 3* of timing across the board, and increased the 2-3 shift a hair. Made a HUGE difference in power. Still ran it on 87 octane. I am sure there was still more to be had, but the truck was stolen when I was down in Knoxville
    The only mod to do to your air system is to block off the silencer (basically a free mod). Other than that, it is more than efficient for the crap factory intake manifold. Leave your air intake alone, do not mess with the throttle blade or MAF sensor. When the time comes (if not already), and you need to replace the spider fuel assembly, you will understand why modding the other portions of the air intake system is pointless.
    '99 Trans Am 416/T56 10.58 1/4. Best trap speed 130.79mph
    '06 GMC Sierra 1500 stock,285s, LQ9 tuned with EFILive
    '91 RS, '91 Z28 both patiently waiting their turn for attention
    '98 ext cab Z71* stolen* Gone but not forgotten.

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    Did someone say ponies? The Fiddle's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Quote Originally Posted by Ghostyman25 View Post
    At least say it doesnt have stock exhaust under it!
    Stock manifolds, stock headpipes, stock cats....glasspacks.



    I'm keeping a hell of a leash on it right now. lol
    2005 Pontiac GTO LS2/A4. FPFQ'ing the GTO community.
    1999 OBS K1500 Black Bear tuned 383 Z71. 2" rear blocks, Hankook MT's. Still around.

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    Registered User shealyn1's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Quote Originally Posted by The Fiddle View Post
    I'm keeping a hell of a leash on it right now. lol
    Understatement of the year award winner right there.

    96 C1500 ecsb body lift and 33s
    2000 K1500 ecsb stock keys decranked and blocks removed

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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Awesome thanks for the help guys! I see a Blackbear tune in my future lol
    '98 chevy silverado ecsb- true dual exhaust, two Flowmaster Super 44 mufflers, 4" ss tips, coil spring spacers, 31X10.5X15 BFG T/A KO tires, 5% tint all around, Kenwood Excelon speakers/headunit, 6000K HID's

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    Registered User 96ImpSS's Avatar
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    Re: 98 5.7 Vortec Performance Upgrade Questions

    Quote Originally Posted by r90camarors View Post
    I think you'll be surprised by what a tune will do for you. Off the top of my head, I removed all of the brake tq management, removed the 4 second PE enable delay, turned off abuse mode, added 3* of timing across the board, and increased the 2-3 shift a hair. Made a HUGE difference in power. Still ran it on 87 octane. I am sure there was still more to be had, but the truck was stolen when I was down in Knoxville
    The only mod to do to your air system is to block off the silencer (basically a free mod). Other than that, it is more than efficient for the crap factory intake manifold. Leave your air intake alone, do not mess with the throttle blade or MAF sensor. When the time comes (if not already), and you need to replace the spider fuel assembly, you will understand why modding the other portions of the air intake system is pointless.
    This guy gets it ;)
    '98 XCSB, ZZ4 cam, Tri-Y's, Yank SS3600 TC
    PCMFORLESS.COM 87 octane tune
    14.30 @ 92.2 on motor
    13.47 @ 99.2 w/ a 50 dry shot

    '96 ImpalaSS
    10.98 @ 122 NA, 10.35 @ 128 on a 100 shot
    stock bottom LT1

 

 

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